Spam continues to plague the internet because a small number of Internet Service Providers knowingly sell service to professional spammers for profit, or do not enough or nothing to prevent spammers operating from their networks.

The World's Worst Spam Support ISPs

As of 19 December 2018the ISPs with the highest numbers of known ongoing spam problems are:

Source: Spamhaus Blocklist (SBL) database. Data is compiled automatically every 24 hours from the SBL database and sorted by the number of currently listed SBL records for each network (ISP/NSP). The source data, including record information on each spam issue listed can be viewed by clicking on the Number of Known Spam Issues links.